This invention pertains to an adjustable work support usable with relatively light loads and which can be operated without deflecting relatively lightweight material which is being supported and accurately held in position.
An adjustable work support for relatively heavy loads is shown in Solie et al U.S. Pat. No. 3,938,798 wherein a plunger is mounted for extension from a casing and is locked in position by movement of a fluid-operated piston which engages a driving pin associated with a number of pins surrounding the plunger whereby compressive force on the driving pin provides frictional forces locking the plunger in position. It is possible in a work support for lighter loads to obtain an air ram effect upon pressurization of the piston whereby air trapped within the unit causes an upward force to be exerted upon the plunger. When supporting a relatively thick, stiff workpiece, this effect is not significant and will be adequately resisted by the workpiece without any deflection thereof. However, such effect could result in deflection of a relatively light metal workpiece.